Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
One of the important drivers for increased performance in semiconductor devices is the higher levels of integration of circuits. This is accomplished by miniaturizing or shrinking device sizes on a given chip. As feature densities in semiconductor devices increase, the widths of the conductive lines and the spacing between the conductive lines and interconnect structures in the semiconductor devices also need to be scaled down.
Although existing methods for forming interconnect structures have been generally adequate for their intended purposes, as device scaling-down continues, they have not been entirely satisfactory in all respects.